CN105493459B - Method and apparatus for transmitting data by using spatial modulation scheme in wireless access system - Google Patents

Abstract

The present invention provides a method for transmitting and receiving data and control signals by applying a spatial modulation scheme to a wireless access system and an apparatus supporting the same. Therefore, according to an embodiment of the present invention, a method of transmitting a data signal by using a Spatial Modulation (SM) scheme transmitter in a wireless access system may include the steps of: selecting two or more transmit antennas for transmitting a data signal; deriving a data bit stream for selecting two or more transmit antennas; configuring a data signal by using an SM scheme based on a data bitstream; and transmitting the configured data signal via the selected two or more transmit antennas.

Description

Method and apparatus for transmitting data by using spatial modulation scheme in wireless access system

Technical Field

The present invention relates to a method for transmitting and receiving data and control signals by applying a spatial modulation scheme to a wireless access system and an apparatus for supporting the same.

Background

Wireless access systems have been widely deployed to provide various types of communication services such as voice or data. Generally, a wireless access system is a multiple access system that supports communication of multiple users by sharing available system resources (bandwidth, transmission power, etc.) among them. For example, multiple-access systems include Code Division Multiple Access (CDMA) systems, Frequency Division Multiple Access (FDMA) systems, Time Division Multiple Access (TDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and single carrier frequency division multiple access (SC-FDMA) systems.

Disclosure of Invention

Technical problem

An object of the present invention is to provide a method of efficiently transmitting and receiving data.

Another object of the present invention is to provide a method of applying a Spatial Modulation (SM) scheme for efficient data transmission and reception.

It is still another object of the present invention to provide a method of transmitting control information by using a spatial modulation scheme for efficient transmission and reception of control information.

It is a further object of the present invention to provide an apparatus for supporting the aforementioned method.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Technical scheme

The present invention relates to a method for transmitting and receiving data and control signals by applying a spatial modulation scheme to a wireless access system and an apparatus for supporting the same.

In one aspect of the present invention, a method for transmitting a data signal from a transmitter by using a Spatial Modulation (SM) scheme in a wireless access system, comprises the steps of: selecting two or more antennas for transmitting data signals; deriving a data bit stream for selecting two or more transmit antennas; configuring a data signal by using an SM scheme based on a data bitstream; and transmitting the configured data signal through two or more transmit antennas.

The method may further include the step of transmitting information on a rank for transmitting the configured data signal if the rank is 2 or more. At this time, the configured data signal may be transmitted together with the UE-specific reference signal matched to each of the two or more transmission antennas. Also, the configured data signal may be an E-PDCCH (enhanced physical downlink control channel) signal of control information transmitted from the data region. Also, an ACK/NACK signal, a New Data Indicator (NDI) or Transmit Power Control (TPC) information may be mapped to the data bit stream.

Otherwise, systematic bits of the input bits may be mapped to data bits for selecting two or more antennas.

Otherwise, parity bits of the input bits may be mapped to data bits for selecting two or more antennas.

In another aspect of the present invention, a method for receiving a data signal at a receiver by using a Spatial Modulation (SM) scheme in a wireless access system, comprises the steps of: detecting an antenna port of a transmitter to which the received data signal is transmitted; deriving a data bit stream implied by the antenna port; and demodulating the received data signal based on a data bit stream, wherein the data bit stream means a bit stream used by the transmitter to select an antenna port.

The method may further comprise the step of receiving information about the rank of the received data signal. At this time, the received data signal may be transmitted together with the UE-specific reference signal matched to the transmitting antenna of the transmitter. The received data signal may be an E-PDCCH (enhanced physical downlink control signal) of control information transmitted from a data region. Also, an ACK/NACK signal, a New Data Indication (NDI), or Transmit Power Control (TPC) information may be mapped to the data bit stream.

Otherwise, systematic bits of the input bits may be mapped to the data bit stream. Otherwise, parity bits of the input bits may be mapped to the data bit stream.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Advantageous effects

As is apparent from the above description, the embodiments of the present invention have the following effects.

First, additional data or control information can be transmitted through a small number of bits, so that data can be efficiently transmitted and received.

Second, the data signal can be transmitted together with the control information.

Again, the systematic bits or the parity bits can be matched to the bit stream for antenna selection during transmission of the data signal, so that more reliable data transmission can be performed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

Fig. 1 is a conceptual diagram illustrating physical channels used in an embodiment and a signal transmission method using the physical channels.

Fig. 2 is a diagram illustrating the structure of a radio frame used in the embodiment.

Fig. 3 is a diagram illustrating an example of a resource grid of a downlink slot according to an embodiment.

Fig. 4 is a diagram illustrating a structure of an uplink subframe according to an embodiment.

Fig. 5 is a diagram illustrating a structure of a downlink subframe according to an embodiment.

Fig. 6 is a diagram illustrating an example of Component Carriers (CCs) used in an embodiment of the present invention and carrier aggregation used in an LTE-a system.

Fig. 7 is a diagram illustrating a subframe frame structure of an LTE-a system according to cross-carrier scheduling used in an embodiment of the present invention.

Fig. 8 is a diagram illustrating physical mapping of PUCCH formats to PUCCH RBs.

Fig. 9 is a diagram illustrating PUCCH formats 2/2a/2b in the case of a normal cyclic prefix.

Fig. 10 is a diagram illustrating PUCCH formats 2/2a/2b in the case of an extended cyclic prefix.

Fig. 11 is a diagram illustrating PUCCH formats 1a/1b in the case of a normal cyclic prefix.

Fig. 12 is a diagram illustrating PUCCH formats 1a/1b in the case of an extended cyclic prefix.

Fig. 13 is a diagram illustrating one of constellation mappings of HARQ ACK/NACK for a normal CP.

Fig. 14 is a diagram illustrating joint coding performed by HARQ ACK/NACK and CQI for an extended CP.

Fig. 15 is a diagram illustrating one of methods for multiplexing SR and ACK/NACK signals.

Fig. 16 is a diagram illustrating constellation mapping of ACK/NACK and SR for PUCCH format 1/1a/1 b.

Fig. 17 is a diagram illustrating a method of matching control information and a physical resource region.

Fig. 18 is a diagram illustrating an example of an encoding method based on a dual RM scheme.

Fig. 19 is a diagram illustrating a method for interleaving output code bits when the dual RM described in fig. 18 is used.

Fig. 20 is a diagram illustrating the concept of a spatial modulation scheme.

Fig. 21 is a diagram illustrating one of methods of transmitting and receiving data/control signals by using a Spatial Modulation (SM) scheme to which spatial multiplexing is applied.

Fig. 22 is a diagram illustrating a method for applying a Spatial Modulation (SM) scheme to systematic bits and parity bits of a configuration data signal.

Fig. 23 is a diagram illustrating one of methods for configuring a data signal in a transmitter by applying a Spatial Modulation (SM) scheme.

Fig. 24 is a diagram illustrating an example of a method for transmitting turbo bits by applying a Spatial Modulation (SM) scheme to the turbo bits.

Fig. 25 is a diagram of an apparatus by which the method described in fig. 1 to 24 can be embodied.

Detailed Description

Embodiments of the present invention described in detail below relate to a method of transmitting and receiving data and control signals by using a spatial modulation scheme and an apparatus for supporting the same.

The embodiments of the present disclosure described below are combinations of elements and features of the present disclosure in specific forms. Elements or features may be considered optional unless otherwise specified. Each element or feature may be implemented without being combined with other elements or features. Further, the embodiments of the present disclosure may be configured by combining parts of the elements and/or features. The order of operations described in the embodiments of the present disclosure may be rearranged. Some configurations or elements of any one embodiment may be included in another embodiment, and may be replaced with corresponding configurations or features of another embodiment.

In the description of the drawings, detailed descriptions of known processes or steps of the present disclosure will be avoided so as not to obscure the subject matter of the present disclosure. In addition, processes or steps that can be understood by those skilled in the art will not be described.

Throughout this specification, when a certain part "includes" or "includes" a certain component, this indicates that other components are not excluded and may be further included unless otherwise specified in clear text. The terms "unit", "device", and "module" described in the specification indicate a unit for processing at least one function or operation implemented by hardware, software, or a combination thereof. In addition, the terms "a" or "an", "the", and the like, in the context of the present invention (and more particularly, in the context of the following claims) may include both singular and plural referents unless otherwise indicated herein or clearly contradicted by context.

In the embodiments of the present disclosure, description is mainly made in terms of a data transmission and reception relationship between a Base Station (BS) and a User Equipment (UE). The BS refers to a terminal node of a network, which directly communicates with the UE. Certain operations described as being performed by the BS may be performed by an upper node of the BS.

That is, it is apparent that, in a network configured by a plurality of network nodes including a BS, the BS or a network node other than the BS may perform various operations performed for communication with a UE. The term "BS" may be replaced with the terms fixed station, node B, evolved node B (enodeb or eNB), Advanced Base Station (ABS), Access Point (AP), etc.

In the embodiments of the present disclosure, the term terminal may be replaced with a UE, a Mobile Station (MS), a Subscriber Station (SS), a mobile subscriber station (MSs), a mobile terminal, an Advanced Mobile Station (AMS), and the like.

The transmitter is a fixed and/or mobile node that provides data services or voice services, and the receiver is a fixed and/or mobile node that receives data services or voice services. Thus, on the Uplink (UL), the UE may act as a transmitter and the BS may act as a receiver. Likewise, on the Downlink (DL), the UE may serve as a receiver and the BS may serve as a transmitter.

Exemplary embodiments of the present disclosure are supported by a disclosed standard specification of a wireless access system including at least one of an Institute of Electrical and Electronics Engineers (IEEE) 802.xx system, a third generation partnership project (3GPP) system, a 3GPP Long Term Evolution (LTE) system, and a 3GPP2 system. Specifically, embodiments of the present disclosure may be supported by standard specifications of 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.321, and 3GPP TS 36.331. That is, steps or portions, which are not described in the embodiments of the present disclosure to clearly disclose the technical idea of the present disclosure, may be supported by the above standard specifications. All terms used in the embodiments of the present disclosure may be interpreted by a standard specification.

Reference will now be made in detail to embodiments of the present disclosure with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure, rather than to show only embodiments that can be implemented according to the present invention.

The following detailed description includes specific nomenclature to provide a thorough understanding of the disclosure. However, it will be apparent to those skilled in the art that specific terms may be substituted for other terms without departing from the technical spirit and scope of the present disclosure.

For example, an antenna refers to a physical antenna, and an antenna port is a logical concept of matching a specific physical antenna. However, in embodiments of the present invention, the antenna and the antenna port may be used to refer to the same meaning unless otherwise specified in the clear.

Hereinafter, an exemplary 3gpp LTE/LTE-a system capable of being applied to the wireless access system of the embodiment of the present invention will be explained.

Embodiments of the present disclosure can be applied to various wireless access systems such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like.

CDMA may be implemented as a wireless communication technology such as Universal Terrestrial Radio Access (UTRA) or CDMA 2000. The TDMA may be implemented as a radio technology such as global system for mobile communications (GSM)/General Packet Radio Service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented as a radio technology such as IEEE 802.11 (Wi-Fi), IEEE802.16(WiMAX), IEEE 802.20, evolved UTRA (E-UTRA), and so on.

UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP LTE is part of an evolved UMTS (E-UMTS) using E-UTRA, which employs OFDMA for the DL and SC-FDMA for the UL. LTE-advanced (LTE-A) is an evolution of 3GPP LTE. Although the embodiments of the present disclosure are described in the context of a 3GPP LTE/LTE-a system in order to clarify technical features of the present disclosure, the present disclosure may also be applicable to an IEEE802.16 e/m system and the like.

1.3 GPP LTE/LTE-A system

In a wireless access system, a UE receives information from an eNB on DL and transmits information to the eNB on UL. Information transmitted and received between the UE and the eNB includes general data information and various types of control information. There are various physical channels according to the type/use of information transmitted and received between the eNB and the UE.

1.1 System overview

Fig. 1 illustrates physical channels and a general method of using the physical channels that may be used in an embodiment of the present disclosure.

When the UE is powered on or enters a new cell, the UE performs an initial cell search (S11). Initial cell search involves acquisition synchronized with the eNB. Specifically, the UE may synchronize timing with the eNB and acquire information, such as a cell Identifier (ID), by receiving a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from the eNB.

The UE may then acquire the information broadcast in the cell by receiving a Physical Broadcast Channel (PBCH) from the eNB.

During initial cell search, the UE may monitor a downlink reference signal (DL RS) channel state by receiving a DL RS.

After the initial cell search, the UE may acquire more detailed system information by receiving a Physical Downlink Shared Channel (PDSCH) and receiving a Physical Downlink Control Channel (PDCCH) based on information of the PDCCH (S12).

To complete the connection to the eNB, the UE may perform a random access procedure with the eNB (S13 to S16). In the random access procedure, the UE may transmit a preamble on a Physical Random Access Channel (PRACH) (S13), and may receive the PDCCH and a PDSCH associated with the PDCCH (S14). In case of contention-based random access, the UE may additionally perform a contention resolution procedure including transmission of an additional PRACH (S15) and reception of a PDCCH signal and a PDSCH signal corresponding to the PDCCH signal (S16).

After the above procedure, the UE may receive a PDCCH and/or a PDSCH from the eNB (S17) and may transmit a Physical Uplink Shared Channel (PUSCH) and/or a Physical Uplink Control Channel (PUCCH) to the eNB (S18) in a general UL/DL signal transmission procedure.

The control information transmitted by the UE to the eNB is generally referred to as Uplink Control Information (UCI). The UCI includes hybrid automatic repeat request acknowledgement/negative acknowledgement (HARQ-ACK/NACK), Scheduling Request (SR), Channel Quality Indication (CQI), Precoding Matrix Index (PMI), Rank Indication (RI), and the like.

In the LTE system, UCI is generally transmitted periodically on PUCCH. However, if the control information and the traffic data should be transmitted simultaneously, the control information and the traffic data may be transmitted on the PUSCH. In addition, UCI may be transmitted on PUSCH aperiodically upon receiving a request/command from the network.

Fig. 2 illustrates an exemplary radio frame structure used in embodiments of the present disclosure.

Fig. 2(a) illustrates a frame structure type 1. Frame structure type 1 may be applicable to both full Frequency Division Duplex (FDD) systems and half FDD systems.

One radio frame is 10ms (T)_f＝307200·T_s) Long, 20 slots of equal size, including indices 0 through 19. Each slot is 0.5ms (T)_slot＝15360·T_s) Long. One subframe includes two consecutive slots. The ith subframe includes the 2i and (2i +1) th slots. That is, the radio frame includes 10 subframes. The time required to transmit one subframe is defined as a Transmission Time Interval (TTI). Ts is as_s＝1/(15kHzx2048)＝3.2552x10^-8(about 33ns) is given as the sample time. One slot includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols in a time domain or SC-FDMA symbols multiplied by a plurality of Resource Blocks (RBs) in a frequency domain.

A slot includes a plurality of OFDM symbols in the time domain. Since the DL employs OFDMA in the 3GPP LTE system, one OFDM symbol represents one symbol period. The OFDM symbol may be referred to as an SC-FDMA symbol or a symbol period. An RB is a resource allocation unit including a plurality of consecutive subcarriers in one slot.

In a full FDD system, each of 10 subframes may be used for DL transmission and UL transmission simultaneously for a duration of 10-ms. DL transmissions and UL transmissions are distinguished by frequency. On the other hand, the UE cannot simultaneously perform transmission and reception in the semi-FDD system.

The above radio frame structure is merely exemplary. Thus, the number of subframes in a radio frame, the number of slots in a subframe, and the number of OFDM symbols in a slot may be changed.

Fig. 2(b) illustrates a frame structure type 2. The frame structure type 2 is applied to a Time Division Duplex (TDD) system. One radio frame is 10ms (T)_f＝307200·T_s) Long, including all having 5ms (═ 153600. T)_s) Two half frames in length. Each field includes a field length of 1ms (═ 30720. T)_s) Five subframes long. The ith sub-frame includes all of the sub-frames having a length of 0.5ms (T)_slot＝15360·T_s) 2i and (2i +1) th time slot. T is_sIs given a T_s＝1/(15kHzx2048)＝3.2552x10^-8(about 33 ns).

Type 2 frames include a special subframe having three fields, a downlink pilot time slot (DwPTS), a Guard Period (GP), and an uplink pilot time slot (UpPTS). The DwPTS is used for initial cell search, synchronization, or channel estimation at the UE, and the UpPTS is used for channel estimation at the eNB and UL transmission synchronization with the UE. The GP is used to cancel UL interference between UL and DL caused by multipath delay of DL signals.

The special subframe configuration (DwPTS/GP/UpPTS length) is listed below [ Table 1 ].

[ Table 1]

Fig. 3 illustrates an exemplary structure of a DL resource grid for the duration of one DL slot that may be used in embodiments of the present disclosure.

Referring to fig. 3, a DL slot includes a plurality of OFDM symbols in the time domain. One DL slot includes 7 OFDM symbols in the time domain and 12 subcarriers in the frequency domain, to which the present disclosure is not limited.

Each element of the resource grid is referred to as a Resource Element (RE). RB includes 12 × 7 REs. The number of RBs in the DL slot, NDL, depends on the DL transmission bandwidth. The UL slot may have the same structure as the DL slot.

Fig. 4 illustrates a structure of a UL subframe that may be used in an embodiment of the present disclosure.

Referring to fig. 4, a UL subframe may be divided into a control region and a data region in a frequency domain. A PUCCH carrying UCI is allocated to the control region and a PUSCH carrying user data is allocated to the data region. In order to maintain the single carrier characteristic, the UE does not simultaneously transmit the PUCCH and the PUSCH. A pair of RBs in a subframe is allocated to a PUCCH of a UE. The RBs of the RB pair occupy different subcarriers in two slots. So it can be said that RB pairs hop on slot boundaries.

Fig. 5 illustrates a structure of a DL subframe that may be used in an embodiment of the present disclosure.

Referring to fig. 5, up to 3 OFDM symbols of a DL subframe starting from OFDM symbol 0 are used as a control region to which a control channel is allocated, and the other OFDM symbols of the DL subframe are used as a data region to which a PDSCH is allocated. DL control channels defined by the 3GPP LTE system include a Physical Control Format Indicator Channel (PCFICH), a PDCCH, and a physical hybrid ARQ indicator channel (PHICH).

The PCFICH is transmitted in the first OFDM symbol of the subframe, which carries information about the number of OFDM symbols used for transmission of control channels (i.e., the size of the control region) in the subframe. The PHICH is a response channel to UL transmission, and transmits an harq ack/NACK signal. Control information carried on the PDCCH is referred to as Downlink Control Information (DCI). The DCI conveys UL resource assignment information, DL resource assignment information, or UL transmission (Tx) power control commands for a UE group.

1.2 Physical Downlink Control Channel (PDCCH)

1.2.1 PDCCH overview

The PDCCH may transmit information on resource allocation and a transport format for a downlink shared channel (DL-SCH) (i.e., DL grant), information on resource allocation and a transport format for an uplink shared channel (UL-SCH) (i.e., UL grant), paging information for a Paging Channel (PCH), system information on the DL-SCH, information on resource allocation for a higher layer control message such as a random access response transmitted on the PDSCH, a set of transmission power control commands for individual UEs of a UE group, voice over internet protocol (VoIP) activation indication information, and the like.

Multiple PDCCHs may be transmitted in the control region. The UE may monitor multiple PDCCHs. The PDCCH is formed by aggregating one or more consecutive Control Channel Elements (CCEs). A PDCCH consisting of one or more consecutive CCEs may be transmitted in the control region after sub-block interleaving. The CCE is a logical allocation unit for providing the PDCCH at a coding rate based on a state of a radio channel. The CCE includes a plurality of Resource Element Groups (REGs). The number of available bits for the PDCCH and the format of the PDCCH are determined according to the relationship between the number of CCEs and the coding rate provided by the CCEs.

1.2.2 PDCCH structure

Multiple PDCCHs for multiple UEs may be multiplexed and transmitted in the control region. The PDCCH consists of an aggregation of one or more consecutive CCEs. A CCE is a unit of 9 REGs including 4 REs per REG. A Quadrature Phase Shift Keying (QPSK) symbol is mapped to each REG. REs occupied by the RS are excluded from the REG. That is, the total number of REGs in an OFDM symbol may vary according to whether a cell-specific RS exists. The concept of REGs to which four REs are mapped may also be applied to other DL control channels (e.g., PCFICH or PHICH). Passing the number of REGs not allocated to PCFICH or PHICH over N_REGAnd (4) showing. The number of CCEs available to the system is then

And CCEs are indexed from 0 to NCCE-1.

To simplify the decoding process for the UE, a PDCCH format comprising n CCEs may start with a CCE having an index equal to a multiple of n. That is, given CCE i, the PDCCH format may start with CCEs that satisfy i mod n ═ 0.

The eNB may configure the PDCCH using 1,2,4, or 8 CCEs. {1,2,4,8} is called CCE aggregation level. The number of CCEs used for transmission of the PDCCH is determined by the eNB according to the channel status. For example, one CCE is sufficient for a PDCCH directed to a UE in a good DL channel state (a UE near the eNB). On the other hand, a PDCCH directed to a UE in a bad DL channel state (a UE at a cell edge) may require 8 CCEs in order to confirm sufficient robustness.

The following [ table 2] shows the PDCCH format. 4 PDCCH formats are supported according to CCE aggregation levels as illustrated in table 2.

[ Table 2]

A different CCE aggregation level is allocated to each UE because the format or Modulation and Coding Scheme (MCS) level of the control information transmitted on the PDCCH is different. The MCS level refers to a coding rate and a modulation order used for data coding. The adaptive MCS level is used for link adaptation. In general, 3 or 4 MCS levels may be considered for the control channel carrying the control information.

Regarding the format of the control information, the control information transmitted on the PDCCH is referred to as DCI. The configuration of information in the PDCCH payload may vary according to the DCI format. The PDCCH payload refers to information bits. The DCI is tabulated according to DCI format table 3.

[ Table 3]

DCI format	Description of the invention
		Format
0	Resource grant for PUSCH transmission (uplink)
		Format 1	For single codeword PUSCH transmissionResource assignment for modes 1,2, and 7)
Format 1A	Compact signaling for resource assignment for single codeword PDSCH (all modes)
		Format 1B	Compact resource assignment for PDSCH (mode 6) using rank 1 closed-loop precoding
Format 1C	Very compact resource assignment for PDSCH (e.g., paging/broadcast system information)
		Format 1D	Compact resource assignment for PDSCH (mode 5) using multi-user MIMO
Format
	2	Resource assignment for PDSCH for closed-loop MIMO operation (mode 4)
Format 2A			Resource assignment for PDSCH for open-loop MIMO operation (mode 3)
	Format 3/3A	Power control commands for PUCCH and PUSCH with 2-bit/1-bit power adjustment
Format
	4	Scheduling of PUSCH in one UL cell with multi-antenna port transmission mode

Referring to [ table 3], the DCI formats include format 0 for PUSCH scheduling, format 1 for single codeword PDSCH scheduling, format 1A for compact single codeword PDSCH scheduling, format 1C for very compact DL-SCH scheduling, format 2 for PDSCH scheduling in closed spatial multiplexing mode, format 2A for PDSCH scheduling in open spatial multiplexing mode, and format 3/3a for transmission of TPC commands for UL channels. DCI format 1A may be used for PDSCH scheduling regardless of a transmission mode of the UE.

The length of the PDCCH payload may vary with the DCI format. In addition, the type and length of the PDCCH payload may be changed according to compact or non-compact scheduling or a transmission mode of the UE.

The transmission mode of the UE may be configured for DL data reception on the PDSCH at the UE. For example, DL data carried on the PDSCH includes scheduling data for the UE, paging messages, random access responses, broadcast information on BCCH, and the like. The DL data of the PDSCH is related to a DCI format signaled by the PDCCH. The transmission mode may be semi-statically configured through higher layer signaling (e.g., Radio Resource Control (RRC) signaling). The transmission mode may be classified into single antenna transmission or multi-antenna transmission.

The transmission mode is semi-statically configured for the UE through higher layer signaling. For example, the multi-antenna transmission scheme may include transmit diversity, open or closed loop spatial multiplexing, multi-user multiple input multiple output (MU-MIMO), or beamforming. The transmit diversity increases transmission reliability by transmitting the same data using a plurality of Tx antennas. Spatial multiplexing simultaneously transmits different data through a plurality of Tx antennas for high-speed data transmission without increasing the system bandwidth. Waveform shaping is a technique of increasing a signal to interference and noise ratio (SINR) of a signal by weighting a plurality of antennas according to a channel state.

The DCI format for a UE depends on the transmission mode of the UE. The UE has a reference DCI format monitored according to a transmission mode configured for the UE. The following 10 transmission modes are available to the UE:

(1) transmission mode 1: single antenna port (port 0);

(2) transmission mode 2: transmit diversity;

(3) transmission mode 3: open loop spatial multiplexing when the number of layers is greater than 1, or transmit diversity when the rank is 1;

(4) transmission mode 4: closed-loop spatial multiplexing;

(5) transmission mode 5: MU-MIMO;

(6) transmission mode 6: closed-loop rank-1 precoding;

(7) transmission mode 7: precoding to support non-codebook based single layer transmission (release 8);

(8) transmission mode 8: support precoding of up to two layers not based on a codebook (version 9);

(9) transmission mode 9: support precoding of up to eight layers not based on a codebook (version 10); and

(10) transmission mode 10: up to eight layer precoding without codebook for CoMP is supported (release 11).

1.2.3.PDCCH Transmission

The eNB determines a PDCCH format according to DCI to be transmitted to the UE and adds a Cyclic Redundancy Check (CRC) to the control information. The CRC is masked by a unique Identifier (ID), e.g., a Radio Network Temporary Identifier (RNTI), according to an owner or usage of the PDCCH. If the PDCCH is directed to a specific UE, the CRC may be masked by a unique ID of the UE, e.g., cell RNTI (C-RNTI). If the PDCCH carries a paging message, the CRC may be masked by a paging indication ID (e.g., paging RNTI (P-RNTI)). If the PDCCH carries system information, the CRC may be masked by a system information ID (e.g., system information RNTI (SI-RNTI)), in particular. In order to indicate that the PDCCH carries a random access response to a random access preamble transmitted by the UE, the CRC may be masked by a random access RNTI (RA-RNTI).

The eNB then generates coded data by channel coding the CRC-added control information. Channel coding may be performed at a coding rate corresponding to the MCS level. The eNB rate-matches the coded data according to the CCE aggregation level allocated to the PDCCH format and generates modulation symbols by modulating the coded data. Here, a modulation order corresponding to the MCS level may be used for modulation. The CCE aggregation level for the modulation symbols of the PDCCH may be one of 1,2,4, and 8. Subsequently, the eNB maps the modulation symbols to physical REs (i.e., CCE to RE mapping).

1.2.4 Blind Decoding (BD)

Multiple PDCCHs may be transmitted in a subframe. That is, the control region of the subframe includes a plurality of CCEs, CCE 0 through CCENCCE, k-1. NCCE, k is the total number of CCEs in the control region of the kth subframe. The UE monitors a plurality of PDCCHs in each subframe. This means that the UE attempts to decode each PDCCH according to the monitored PDCCH format.

The eNB does not provide the UE with information about the location of the PDCCH directed to the UE in the allocated control region of the subframe. Without knowledge of the location, CCE aggregation level, or DCI format of its PDCCH, the UE searches for its PDCCH by monitoring the set of PDCCH candidates in the subframe in order to receive the control channel from the eNB. This is called blind decoding. Blind decoding is a process by which the UE masks the CRC part with the UE ID, checks the CRC error, and determines whether the corresponding PDCCH is a control channel directed to the UE.

The UE monitors the PDCCH in every subframe to receive data to be transmitted to the UE in an active mode. In a Discontinuous Reception (DRX) mode, the UE wakes up in a monitoring interval of each DRX cycle and monitors a PDCCH in a subframe corresponding to the monitoring interval. The subframes in which the PDCCH is monitored are referred to as non-DRX subframes.

To receive its PDCCH, the UE should blind decode all CCEs of the control region of the non-DRX subframe. Without knowledge of the transmitted PDCCH format, the UE should decode all DPCCHs with all possible CCE aggregation levels until the UE succeeds in blind decoding the PDCCH in every non-DRX subframe. Since the UE does not know the number of CCEs for its PDCCH, the UE should attempt detection through all possible CCE aggregation levels until the UE succeeds in blind decoding of the PDCCH.

In LTE systems, the concept of Search Space (SS) is defined for blind decoding of UEs. An SS is a set of PDCCH candidates that the UE will monitor. The SSs may have different sizes for each PDCCH format. There are two types of SSs, Common Search Spaces (CSSs) and UE-specific/dedicated search spaces (USSs).

Although all UEs may know the size of the CSS, the USS may be configured for each individual UE. Therefore, the UE should monitor both the CSS and USS to decode the PDCCH. Therefore, the UE performs a maximum of 44 blind decodes in one subframe except for blind decodes based on different CRC values (e.g., C-RNTI, P-RNTI, SI-RNTI, and RA-RNTI).

In view of the limitations of the SS, the eNB may not ensure CCE resources to transmit the PDCCH to all the intended UEs in a given subframe. This situation occurs because the remaining resources except for the allocated CCEs may not be included in the SS for the specific UE. To minimize this obstacle that may continue in the next subframe, a UE-specific hopping sequence may be applied to the start of the USS.

Table 4 illustrates the sizes of the CSS and USS.

[ Table 4]

To reduce the load on the UE caused by the number of blind decoding attempts, the UE does not search for all of the defined DCI formats at the same time. Specifically, the UE always searches for DCI format 0 and DCI format 1A in the USS. Although DCI format 0 and DCI format 1A are the same size, the UE may distinguish the DCI formats by a flag for format 0/format 1A distinction included in the PDCCH. Other DCI formats such as DCI format 1, DCI format 1B, and DCI format 2, in addition to DCI format 0 and DCI format 1A, may be required for the UE.

The UE may search for DCI format 1A and DCI format 1C in the CSS. The UE may be configured to search for DCI format 3 or 3A in the CSS. Although DCI format 3 and DCI format 3A have the same size as DCI format 0 and DCI format 1A, the UE may distinguish the DCI formats by using CRC scrambling except for UE-specific ID.

SS

Is a PDCCH candidate set with CCE aggregation level L e {1,2,4,8 }. The CCE of the PDCCH candidate set in the SS may be determined by the following equation.

[ equation 1]

Wherein M is^(L)Is the number of PDCCH candidates having a CCE aggregation level L to be monitored in the SS, M is 0, …, M^(L)-1, "i" is

Index of CCE in each PDCCH candidate, and i ═ 0, …, L-1.Wherein n is_sIs the index of the slot in the radio frame.

As described previously, the UE monitors both the USS and the CSS to decode the PDCCH. CSS supports PDCCH with CCE aggregation level {4,8}, and USS supports PDCCH with CCE aggregation level {1,2,4,8 }. Table 5 illustrates PDCCH candidates monitored by the UE.

[ Table 5]

Reference [ equation 1]]For two aggregation levels, L-4 and L-8, Y in CSS_kIs set to 0 and passes [ equation 2] for the aggregation level L in the USS]Definition of Y_k。

[ equation 2]

Y_k＝(A·Y_k-1)modD

Wherein Y is_-1＝n_RNTI≠0，n_RNTIAn RNTI value is indicated. 39827 and 65537.

1.3. Carrier Aggregation (CA) environment

1.3.1 overview of CA

The 3GPP LTE system (following release 8 or release 9) (hereinafter, referred to as an LTE system) uses a multi-carrier modulation (MCM) in which a single Component Carrier (CC) is divided into a plurality of frequency bands. In contrast, a 3GPP LTE-a system (hereinafter, referred to as an LTE-a system) may use CA by aggregating one or more CCs, thereby supporting a wider system bandwidth than the LTE system. The term CA is interchangeable with carrier combining, a multi-CC environment, or a multi-carrier environment.

In the present disclosure, multi-carrier means CA (or carrier combination). At this time, the CA covers aggregation of contiguous carriers and aggregation of non-contiguous carriers. The number of aggregated CCs may be different for DL and UL. If the number of DL CCs is equal to the number of ULCCs, this is called symmetric aggregation. If the number of DL CCs is different from the number of UL CCs, this is called asymmetric aggregation. The term CA is interchangeable with carrier combination, bandwidth aggregation, spectrum aggregation, etc.

The LTE-a system aims to support a bandwidth of up to 100MHz by aggregating two or more CCs, that is, by CA. To ensure backward compatibility with legacy IMT systems, each of the one or more carriers, having a bandwidth smaller than the target bandwidth, may be limited to the bandwidth used in legacy systems.

For example, legacy 3GPP LTE systems support bandwidths {1.4,3,5,10,15, and 20MHz }, and 3GPP LTE-a systems can support bandwidths wider than 20MHz using these LTE bandwidths. The CA system of the present disclosure can support CA by defining a new bandwidth regardless of the bandwidth used in the conventional system.

There are two types of CA, intra-band CA and inter-band CA. Intra-band CA means that a plurality of DL CCs and/or UL CCs are all frequency contiguous or adjacent. In other words, carrier frequencies of DL CCs and/or UL CCs are located in the same frequency band. On the other hand, an environment in which the frequencies of CCs are far apart from each other may be referred to as inter-band CA. In other words, carrier frequencies of multiple DL CCs and/or ul CCs are located in different frequency bands. In this case, the UE may communicate in a CA environment using a plurality of Radio Frequency (RF) terminals.

The LTE-a system manages radio resources using the concept of a cell. The CA environment described above may be referred to as a multi-cell environment. Although UL resources are not necessary, a cell is defined as a pair of DL and UL CCs. Therefore, the cell may be configured with separate DL resources or DL and UL resources.

For example, if one serving cell is configured for a specific UE, the UE may have one DL CC and one UL CC. If two or more serving cells are configured for the UE, the UE may have as many DL CCs as the number of serving cells and as many UL CCs as or less than the number of serving cells, or vice versa. That is, if a plurality of serving cells are configured for the UE, it is also possible to support a CA environment using more UL CCs than DL CCs.

CA may be viewed as an aggregation of two or more cells with different carrier frequencies (center frequencies). In this context, the term "cell" should be distinguished from "cells" of the geographical area covered by the eNB. Hereinafter, intra-band CA is referred to as intra-band multi-cell and inter-band CA is referred to as inter-band multi-cell.

In the LTE-a system, a primary cell (PCell) and a secondary cell (SCell) are defined. The PCell and SCell may serve as serving cells. For a UE in RRC _ CONNECTED state, if CA is not configured for the UE or the UE does not support CA, there is a single serving cell for the UE that includes only the PCell. In contrast, if the UE is in RRC _ CONNECTED state and CA is configured for the UE, there are one or more serving cells for the UE, including the PCell and one or more scells.

The serving cells (PCell and SCell) may be configured by RRC parameters. The physical layer ID of the cell, physcellld, is an integer value from 0 to 503. The short ID of SCell, scelllindex, is an integer value from 1 to 7. The short ID of the serving cell (PCell or SCell), servececellindex, is an integer value from 1 to 7. If ServereCellIndex is 0, this indicates that the ServereCellIndex values for both the PCell and SCell are pre-assigned. That is, the minimum cell ID (or cell index) of the servececellindex indicates the PCell.

PCell refers to a cell (or primary CC) operating at a primary frequency. The UE may use the PCell for initial connection establishment or connection re-establishment. The PCell may be a cell indicated during handover. Also, the PCell is a cell responsible for control-related communication between serving cells configured in a CA environment. That is, PUCCH allocation and transmission of the UE may occur only in the PCell. Further, the UE may acquire system information or change a monitoring procedure using only the PCell. An evolved universal terrestrial radio access network (E-UTRAN) may change only a PCell for a handover procedure through a higher layer rrcconnectionreconfiguration message including mobilityControlInfo to a CA-capable UE.

An SCell may refer to a cell (or secondary CC) operating at a secondary frequency. Although only one PCell is allocated to a particular UE, one or more scells may be allocated to the UE. The SCell may be configured after RRC connection establishment and may be used to provide additional radio resources. In cells other than PCell, i.e., scells among serving cells configured in a CA environment, there is no PUCCH.

When the E-UTRAN adds the SCell to the CA-capable UE, the E-UTRAN may transmit all system information related to the operation of the relevant cell in the RRC _ CONNECTED state to the UE through specific signaling. Herein, a higher layer RRCConnectionReconfiguration message may be used. The E-UTRAN may transmit a specific signal with different parameters for each cell instead of broadcasting in the relevant SCell.

After the initial security activation procedure starts, the E-UTRAN may configure a network including one or more scells by adding the SCell to the PCell initially configured during the connection establishment procedure. In a CA environment, each of the PCell and SCell may operate as a CC. Hereinafter, in an embodiment of the present invention, a primary cc (pcc) and a PCell may be used in the same meaning, and a secondary cc (scc) and an SCell may be used in the same meaning.

Fig. 6 illustrates an example of CC and CA in an LTE-a system, which may be used in embodiments of the present disclosure.

Fig. 6(a) shows a single carrier structure in the LTE system. There are DL CCs and UL CCs, and one CC may have a frequency range of 20 MHz.

Fig. 6(b) shows a CA structure in the LTE-a system. In the case shown in fig. 6(b), three CCs each having 20MHz are aggregated. Although three DL CCs and three UL CCs are configured, the number of DL CCs and UL CCs is not limited. In CA, a UE may simultaneously monitor three CCs, receive DL signals/DL data in the three CCs, and transmit UL signals/UL data in the three CCs.

If a particular cell manages N DL CCs, the network may allocate M (M ≦ N) DL CCs to the UE. The UE may monitor only the M DL CCs and receive DL signals in the M DL CCs. The network may give high priority to L (L ≦ M ≦ N) DL CCs and allocate the primary DL CC to the UE. In this case, the UE should monitor L DL CCs. This may also apply to UL transmissions.

The link between the carrier frequency of the DL resource (or DL CC) and the carrier frequency of the UL resource (or UL CC) may be represented by a higher layer message such as an RRC message or system information. For example, the set of DL resources and UL resources may be configured based on the linking indicated by system information block type 2(SIB 2). Specifically, the DL-UL linkage may refer to a mapping relationship between a DL CC carrying a PDCCH with a UL grant and a UL CC using the UL grant, or a mapping relationship between a DL CC (or UL CC) carrying HARQ data and a UL CC (or DL CC) carrying a HARQ ACK/NACK signal.

1.3.2 Cross-Carrier scheduling

Two scheduling schemes, self-scheduling and cross-carrier scheduling, are defined for the CA system from the perspective of the carrier or serving cell. Cross-carrier scheduling may be referred to as cross-CC scheduling or cross-cell scheduling.

In self-scheduling, a PDCCH (carrying DL grant) and a PDSCH are transmitted in the same DL CC, or a PUSCH is transmitted in a UL CC linked to a DL CC in which a PDCCH (carrying UL grant) is received.

In cross-carrier scheduling, a PDCCH (carrying a DL grant) and a PDSCH are transmitted in different DL CCs, or a PUSCH is transmitted in a UL CC other than a UL CC linked to a DL CC in which the PDCCH (carrying a UL grant) is received.

Cross-carrier scheduling may be UE-specifically activated or deactivated and indicated semi-statically to each UE through higher layer signaling (i.e., RRC signaling).

A Carrier Indication Field (CIF) is necessary in the PDCCH to indicate DL/UL CCs in which PDSCH/PUSCH indicated by the PDCCH is to be transmitted if cross-carrier scheduling is activated. For example, the PDCCH may allocate a PDSCH resource or a PUSCH resource to one of the plurality of CCs through the CIF. That is, when the PDCCH of the DL CC allocates a PDSCH or PUSCH resource to one of the aggregated DL/UL CCs, the CIF is set in the PDCCH. In this case, the DCI format of LTE release 8 may be extended according to CIF. The CIF may be fixed to three bits, and the position of the CIF may be fixed regardless of the DCI format size. Furthermore, the PDCCH structure of LTE release 8 (same coding and same CCE based resource mapping) can be reused.

On the other hand, if a PDCCH transmitted in a DL CC allocates a PDSCH resource of the same DL CC or allocates a PUSCH resource in a single UL CC linked to the DL CC, a CIF is not set in the PDCCH. In this case, the PDCCH structure of LTE release 8 (same coding and same CCE based resource mapping) may be used.

If cross-carrier scheduling is available, the UE needs to monitor a plurality of PDCCHs of DCI according to a transmission mode and/or bandwidth of each CC in a control region of the monitoring CC. Therefore, appropriate SS configuration and PDCCH monitoring are required for this purpose.

In the CA system, a UE DL CC set is a set of DL CCs scheduled by the UE for receiving a PUSCH, and a UE UL CC set is a set of UL CCs scheduled for the UE for transmitting a PUSCH. The PDCCH monitoring set is a set of one or more DL CCs in which a PDCCH is monitored. The PDCCH monitoring set may be the same as the UE DL CCC set or may be a subset of the UE DL CC set. The PDCCH monitoring set may include at least one of DL CCs of the UE DL CC set. Or a PDCCH monitoring set may be defined regardless of the UE DL CC. DL CCs included in the PDCCH monitoring set may be configured to always be self-schedulable for UL CCs linked to DL CCs. The UE DL CC set, the UE UL CC set, and the PDCCH monitoring set may be configured UE-specifically, UE group-specifically, or cell-specifically.

If cross-carrier scheduling is deactivated, this means that the PDCCH monitoring set is always the same as the UE DL CC set. In this case, the PDCCH monitoring set need not be signaled. Then, if cross-carrier scheduling is activated, a PDCCH monitoring set may be defined within the UE DL CC set. That is, the eNB transmits PDCCH only in the PDCCH monitoring set, thereby scheduling PDSCH or PUSCH for the UE.

Fig. 7 illustrates a subframe structure of cross-carrier scheduling in an LTE-a system used in an embodiment of the present disclosure.

Referring to fig. 7, three DL CCs are aggregated for a DL subframe of an LTE-a UE. DL CC 'a' is configured as a PDCCH monitoring DL CC. If CIF is not used, each DL CC may transmit a PDCCH scheduling a PDSCH in the same DL CC without CIF. On the other hand, if CIF is used by higher layer signaling, only DL CC 'a' may carry PDCCH scheduling PDSCH in the same DL CC 'a' or another CC. Herein, no PDCCH is transmitted in DL CC 'B' and DL CC 'C' which are not configured as PDCCH monitoring DL CCs.

2. Control signal transmission through PUCCH (physical uplink control channel)

The PUCCH is an uplink control channel used to transmit Uplink Control Information (UCI). The UCI transmitted on the PUCCH includes Scheduling Request (SR) information, HARQ ACK/NACK information, and CQI information.

The number of control information that the UE can send in a subframe depends on the number of SC-FDMA symbols available for transmission of control signaling data (at this time, SC-FDMA symbols excluding transmission of reference signals for coherent detection of PUCCH). The LTE/LTE-a system supports 7 different PUCCH formats according to information to be signaled on the PUCCH.

The PUCCH may include the following format to transmit control information.

(1) Format 1: on-off keying (OOK) modulation for SR (scheduling request)

(2) Formats 1a and 1 b: for ACK/NACK transmission

1) Format 1 a: BPSK ACK/NACK for 1 codeword

2) Format 1 b: QPSK ACK/NACK for 2 codewords

(3) Format 2: QPSK modulation for CQI Transmission

(4) Format 2a and format 2 b: simultaneous transmission of CQI and ACK/NACK

(5) Format 3: multiple ACK/NACK transmission in a carrier aggregation environment

Table 6 shows modulation schemes according to PUCCH formats and the number of bits per subframe. Table 7 shows the number of Reference Signals (RSs) per slot according to the PUCCH format. Table 8 shows SC-FDMA symbol positions of RSs (reference signals) according to the PUCCH format. In table 6, PUCCH format 2a and PUCCH format 2b correspond to the case of a normal Cyclic Prefix (CP).

[ Table 6]

PUCCH format	Modulation scheme	Number of bits per subframe, Mbit
			1	N/A	N/ A
1a	BPSK
			1
1b	QPSK				2
		2	QPSK			20
2a	QPSK+BPSK			21
		2b	QPSK+BPSK		22
3	QPSK			48

[ Table 7]

PUCCH format	Conventional CP	Extended CP
			1,1a,1b	3	2
2,3	2	1
			2a,2b	2	N/A

[ Table 8]

Fig. 8 is a diagram illustrating physical mapping of PUCCH formats to PUCCH RBs.

Referring to fig. 8, PUCCH formats 2/2a/2b are mapped and allocated to an edge RB of a PUCCH band (e.g., PUCCH region m 0,1), and then a PUCCH RB combining PUCCH formats 2/2a/2b and 1/1a/1b is allocated (e.g., PUCCH region m 2). Next, PUCCH formats 1/1a/1b are allocated to PUCCH RBs (e.g., PUCCH region m ═ i)3,4,5). Number of PUCCH RBs used for PUCCH format 2/2a/2b through broadcast signal

Is transmitted from the cell to the UE. Fig. 8 illustrates an example of allocated PUCCH formats, in which PUCCH formats actually mapped onto PUCCH can be sequentially allocated according to the aforementioned order.

2.1 CQI Transmission over PUCCH Format

Fig. 9 is a diagram showing PUCCH formats 2/2a/2b in the case of a normal cyclic prefix, and fig. 10 is a diagram showing PUCCH formats 2/2a/2b in the case of an extended cyclic prefix.

Both the periodicity and the frequency resolution used by the UE to report CQI are controlled by the eNB. In the time domain, periodicity and aperiodicity are supported

Both CQI reports. PUCCH format 2 is used for periodic CQI reporting only and PUSCH is used for aperiodic reporting of CQI. At this point, the eNB specifically instructs the UE to send a CQI report, which the UE then sends to the resources scheduled for uplink data transmission.

A PUCCH CQI channel structure for one slot in the case of a normal CP will be understood with reference to fig. 9. In this case, SC-FDMA symbols 1 and 5 (i.e., second and sixth symbols) are used for transmission of DM RS (demodulation reference signal). A PUCCH CQI channel structure for one slot in the extended CP case will be understood with reference to fig. 10. In this case, SC-FDMA symbol 3 is used for transmission of DM RS. The DM-RS is a reference signal transmitted by the UE to the uplink, and may be referred to as a ULRS.

The CQI information for a 10-bit channel encoded at an 1/2 coding rate is punctured by a (20, k) Reed-muller (rm) code to give 20 coded bits. The CQI information is then scrambled (e.g., in a manner similar to PUSCH data with a length 31Gold sequence) prior to QPSK constellation mapping. One QPSK modulation symbol is transmitted to each of 10 SC-FDMA symbols in a subframe by modulating a cyclic time shift of a length-12 base RS sequence prior to OFDM modulation. The 12 equidistant cyclic time shifts allow for 12 different UEs to be orthogonally multiplexed on the same CQI PUCCH RB. The DM RS sequence is similar to the frequency domain CQI signal sequence but does not include CQI data modulation.

The UE is configured to determine a cyclic time shift to be used by receiving a PUCCH resource index including a PUCCH region and a cyclic time shift indicating to be usedPeriodically reporting different CQI, PMI and RI types on the CQI PUCCH.

2.2 HARQ ACK/NACK transmission over PUCCH Format 1

Fig. 11 is a diagram showing PUCCH formats 1a/1b in the case of a normal cyclic prefix, and fig. 12 is a diagram showing PUCCH formats 1a/1b in the case of an extended cyclic prefix.

Referring to fig. 11 and 12, in the case of the normal CP, three SC-FDMA symbols in the middle of the slot are used for UL-RS, and in the case of the extended CP, two SC-FDMA symbols in the middle of the slot are used for UL-RS. At this time, both 1 and 2-bit ACK/NACK are modulated using BPSK and QPSK modulation, respectively.

In the case of CQI transmission, one BPSK/QPSK modulation symbol is transmitted on each SC-FDMA data symbol by modulating a cyclic time shift of a length-12 base RS sequence (i.e., frequency-domain CDM) prior to OFDM modulation. In addition, a time domain spreading code having an orthogonal (walsh-hadamard transform of DFT) spreading code is used for the code division multiplexing UE. RSs from different UEs are multiplexed in the same manner as data SC-FDMA symbols.

2.3 multiplexing of CQI and ACK/NACK

In the LTE system, HARQ ACK/NACK and CQI can be simultaneously transmitted through UE-specific higher layer signaling.

In the event that simultaneous transmissions cannot be made and the UE is configured to report CQI on PUCCH of the same subframe that requires HARQ ACK/NACK transmissions, then the CQI report is discarded and the HARQ ACK/NACK is transmitted using only PUCCH format 1a/1 b.

In case of enabling simultaneous transmission, CQI and 1 or 2 bit ACK/NACK need to be multiplexed on the same PUCCH RB while maintaining low cm (cubic metric) single carrier characteristics. The method for achieving this goal is different for the case of normal CP and extended CP.

In case of the normal CP, in order to transmit 1 or 2 bit HARQ ACK/NACK together with CQI, ACK/NACK bits (not scrambled) are BPSK/QPSK modulated as shown in FIG. 13, resulting in a single HARQ ACK/NACK modulation symbol d_HARQ. Fig. 13 is a diagram showing one of constellation mappings of HARQ ACK/NACK for a normal CP. At this time, the ACK signal is encoded as a binary number '1', and the NACK signal is encoded as a binary number '0'. Then using a single HARQ ACK/NACK modulation symbol d_HARQThe second RS symbol (SC-FDMA symbol 5, i.e., RS signaled by ACK/NACK) in each CQI slot is modulated. That is, ACK/NACK is signaled using the corresponding RS.

In case of extended CP with one RS symbol per slot, 1 or 2 bit HARQ ACK/NACK is jointly encoded with CQI, resulting in (20, k)_CQI+k_A/N) Based on Reed-Muller block codes. The 20-bit codeword is transmitted on the PUCCH using the CQI channel structure of fig. 9. Joint coding of ACK/NACK and CQI is performed as shown in fig. 14. The maximum number of information bits supported by a block code is 13. At this time, k_CQI11CQI bits, and k _A/N2 bits.

2.4 multiplexing of SR and ACK/NACK

Fig. 15 is a diagram illustrating one of methods for multiplexing SR and ACK/NACK signals, and fig. 16 is a diagram illustrating constellation mapping of ACK/NACK and SR for PUCCH format 1/1a/1 b.

Referring to fig. 15, if an SR signal and an ACK/NACK signal are simultaneously transmitted in the same subframe, a UE transmits an ACK/NACK signal on an SR PUCCH resource allocated for a positive SR and transmits an ACK/NACK on an ACK/NACK PUCCH resource allocated in the case of a negative SR. The constellation mapping for simultaneously transmitting ACK/NACK and SR is shown in fig. 16.

HARQ ACK/NACK transmission in 2.5 TDD systems

In case of LTE TDD (time division multiplexing), since the UE can receive PDSCH during multiple subframes, the UE can feed back HARQ ACK/NACK for multiple PDSCH to the eNB. That is, there are the following two types of harq ack/NACK transmission schemes.

(1) ACK/NACK bundling

The ACK/NACK responses to the multiple data units are combined by a logical-AND operation through ACK/NACK bundling. For example, if the Rx node (or receiver) successfully decodes all data units, the Rx node transmits an ACK using one ACK/NACK unit. Otherwise, if the Rx node fails in decoding any data unit, the Rx node may send a NACK using one ACK/NACK unit, or send nothing for the ACK/NACK.

(2) ACK/NACK multiplexing

The content of ACK/NACK responses to a plurality of data units is recognized by a combination of one of ACK/NACK and QPSK modulation symbols used in actual ACK/NACK transmission through ACK/NACK multiplexing. For example, if it is assumed that one ACK/NACK unit carries 2 bits and a maximum of two data units are transmitted, the ACK/NACK result can be recognized at the TX node as shown in table 9 below.

[ Table 9]

In table 9, HARQ-ACK (i) indicates ACK/NACK results for data unit i (i.e., there are at most 2 data units, that is, data unit 0 and data unit 1 in this example). In table 9, DTX means that there is no data unit transmitted for the corresponding HARQ-ack (i), or the Rx node does not detect that there is a data unit corresponding to HARQ-ack (i).Indicating ACK/NACK units used in actual ACK/NACK transmission, where there are at most two ACK/NACK units —And

b (0), b (1) indicates the information carried by the selected ACK/NACK unitTwo bits. The modulation symbol transmitted by the ACK/NACK unit is determined according to the bit. For example, if the RX node successfully receives and decodes two data units, the RX node uses an ACK/NACK unit

Two bits (1,1) are sent. As another example, if the Rx node receives two data units, fails to decode the first data unit (corresponding to HARQ-ACK (0)) and succeeds to decode the second data unit (corresponding to HARQ-ACK (1)), the Rx node uses

Two bits (0,0) are sent.

By linking the actual ACK/NACK content with a combination of ACK/NACK unit selection and actual bit content for ACK/NACK unit transmission, ACK/NACK transmission using a single ACK/NACK unit for multiple data units is possible. The example described in table 9 can be extended to ACK/NACK transmission of more than 2 data units.

In the ACK/NACK multiplexing method, if there is at least one ACK for all data units, NACK and DTX are coupled as NACK/DTX shown in table 9. This is because the combination of ACK/NACK elements and QPSK symbols is not sufficient to cover all ACK/NACK hypotheses based on the decoupling of NACK and DTX. On the other hand, for the case where there is no ACK for all data units (in other words, there is only NACK or DTX for all data units), a single explicit NACK case is defined as only one of the HARQ-ACKs (i) being a NACK decoupled from DTX. In this case, an ACK/NACK unit linked to a data unit corresponding to a single explicit NACK can also be reserved to signal multiple ACK/NACKs.

The required ACK/NACK hypothesis for ACK/NACK multiplexing over all data units may increase exponentially as the maximum number of data units that can be transmitted within a given amount of physical resources becomes larger. Representing the maximum number of data units and the corresponding number of ACK/NACKs as N and N, respectively_AFor ACK/NACK multiplexing even if DTX case is excludedNeed 2^NOne ACK/NACK hypothesis. On the other hand, applying a single ACK/NACK unit selection as described above, ACK/NACK multiplexing can be made up of up to 4N_AOne ACK/NACK hypothesis is supported.

In other words, as the number of data units increases, a relatively larger number of ACK/NACK units is required for a single ACK/NACK unit selection, which results in a larger control channel resource overhead required to transmit signals for multiple ACK/NACKs. For example, if 5 data units (N-5) are used for transmission, 8 ACK/NACK units (N) are transmitted for ACK/NACK_A8) should be available because the required number of ACK/NACK hypotheses for ACK/NACK multiplexing is 2^N＝32(＝4N_A)。

2.6 uplink channel coding for PUCCH Format 2

In LTE uplink transmission, a specific control signal is encoded using a linear block code as shown in table 10.

[ Table 10]

If the input bits to the linear block code are denoted as a₀,a₁,a₂,…,a_AThen after coding, the bit is represented by b₀,b₁,b₂,…,b_BWherein B is 20. Equation 3 below indicates one of the methods for generating the coded bits.

[ equation 3]

Wherein i is 0,1,2, …, B-1.

The coded bits are then mapped to code time-frequency resources as shown in fig. 17. Fig. 17 is a diagram illustrating a method of matching control information by a physical resource region. The first 10 code bits are mapped to a particular code time-frequency resource and the last 10 code bits are mapped to a different code time-frequency resource. At this time, the frequency interval between the first 10 coded bits and the last 10 coded bits is generally large, and thus frequency diversity for the coded bits can be obtained.

Uplink channel coding in 2.7 LTE-A systems

As described above, in the LTE system (i.e., release 8), if UCI is transmitted to PUCCH format 2, (20, a) RM encoding of table 10 is performed on CSI of maximum 13 bits. However, if UCI is transmitted to PUSCH, RM encoding of (32, a) of table 11 is performed on CQI of maximum 11 bits, and puncturing or cyclic repetition is performed to match the encoding rate to be transmitted to PUSCH.

[ Table 11]

i	Mi,0	Mi,1	Mi,2	Mi,3	Mi,4	Mi,5	Mi,6	Mi,7	Mi,8	Mi,9	Mi,10
												0	1	1	0	0	0	0	0	0	0	0	1
1	1	1	1	0	0	0	0	0	0	1	1
												2	1	0	0	1	0	0	1	0	1	1	1
3	1	0	1	1	0	0	0	0	1	0	1
												4	1	1	1	1	0	0	0	1	0	0	1
5	1	1	0	0	1	0	1	1	1	0	1
												6	1	0	1	0	1	0	1	0	1	1	1
7	1	0	0	1	1	0	0	1	1	0	1
												8	1	1	0	1	1	0	0	1	0	1	1
9	1	0	1	1	1	0	1	0	0	1	1
												10	1	0	1	0	0	1	1	1	0	1	1
11	1	1	1	0	0	1	1	0	1	0	1
												12	1	0	0	1	0	1	0	1	1	1	1
13	1	1	0	1	0	1	0	1	0	1	1
												14	1	0	0	0	1	1	0	1	0	0	1
15	1	1	0	0	1	1	1	1	0	1	1
												16	1	1	1	0	1	1	1	0	0	1	0
17	1	0	0	1	1	1	0	0	1	0	0
												18	1	1	0	1	1	1	1	1	0	0	0
19	1	0	0	0	0	1	1	0	0	0	0
												20	1	0	1	0	0	0	1	0	0	0	1
21	1	1	0	1	0	0	0	0	0	1	1
												22	1	0	0	0	1	0	0	1	1	0	1
23	1	1	1	0	1	0	0	0	1	1	1
												24	1	1	1	1	1	0	1	1	1	1	0
25	1	1	0	0	0	1	1	1	0	0	1
												26	1	0	1	1	0	1	0	0	1	1	0
27	1	1	1	1	0	1	0	1	1	1	0
												28	1	0	1	0	1	1	1	0	1	0	0
29	1	0	1	1	1	1	1	1	1	0	0
												30	1	1	1	1	1	1	1	1	1	1	1
31	1	0	0	0	0	0	0	0	0	0	0

In the LTE-a system, PUCCH format 3 has been introduced to transmit UCI (a/N and SR) bits of a maximum of 21 bits, and in a state of a normal CP, the UE can transmit coded bits of 48 bits by using PUCCH format 3. Therefore, when the UCI bit number is 11 bits or less, (32, a) RM coding is used, and in this case, cyclic repetition of coded bits is used, thereby corresponding to the coded bits required by PUCCH format 3. If the number of UCI bits exceeds 11 bits, the number of sequences based on the (32, a) RM code in table 11 is insufficient, whereby two coded bits (this case will be referred to as Dual RM) are generated using two (32, a) RM encoded blocks as shown in fig. 18, and the other bits are transmitted by puncturing and interleaving, thereby reducing the number of code bits of two coded bits to correspond to PUCCH format 3.

In the case where UCI of a maximum of 21 bits is transmitted to the PUSCH, puncturing or cyclic repetition is performed using (32, a) RM coding in the same manner as the conventional release 8 system so as to match the coding rate to be transmitted to the PUSCH when the UCI bit number is 11 bits or less, and two coded bits are generated using Dual RM when the UCI bit number exceeds 11 bits, and puncturing or cyclic repetition is performed on the two coded bits so as to match the coding rate to be transmitted to the PUSCH.

Referring to fig. 18, when the number of input UCI bits corresponds to 21 bits, the transmitter generates part 1 and part 2 by dividing the corresponding UCI bits. The transmitter then applies (32, a) RM coding to each of part 1 and part 2 and truncates or cyclically repeats the coded bits to match the 48 bits that can be sent by PUCCH format 3. Then, the transmitter interleaves or concatenates the output coded bits, thereby enabling transmission of the coded bits through PUCCH format 3.

In more detail, a bit configuration order of each UCI will be described. If PUCCH format 3 is configured to be used for SR transmission subframe, when SR and a/N are transmitted to PUCCH format 3 or PUSCH, a/N is arranged first and then SR is arranged next to a/N, thereby configuring UCI bit.

Fig. 19 is a diagram illustrating a method for interleaving output coded bits when the dual RM described in fig. 18 is used. Referring to fig. 19, when data blocks of lengths a and B, i.e., UCI, are input to (32, a) and (32, B) RM encoders, respectively, output coded bits become a0, a1, …, a23 and B0, B1, …, B23 through rate matching of 24 bits.

The coded bits a0, a1, …, a23 and B0, B1, …, B23 are input to the interleaver, and the coded bits output from the interleaver are output in pairs in the proper order, thereby generating bit streams of a0, a1, B0, B1, a2, A3, B2, B3, …, a22, a23, B22 and B23. QPSK-modulating the bit stream according to a PUCCH format 3 transmission format and transmitting the bit stream, wherein the first 24 bits (12 QPSK symbols) of the bit stream are mapped into a first slot and the other 24 bits (12 QPSK symbols) are mapped into a second slot.

3. Spatial modulation

Spatial Modulation (SM) represents the selection of antennas or antenna groups with some input bit streams in a wireless access system supporting UEs and enbs, each of which comprises multiple antennas and transmits other bit streams by mapping on constellation points.

Fig. 20 is a diagram illustrating the concept of a spatial modulation scheme.

Fig. 20(a) shows that 3 bits are transmitted using four transmit (Tx) antennas of a transmitter. At this time, the first 2 bits of the 3-bit stream represent one of four transmission antennas, and the other 1 bit may be transmitted through BPSK modulation. Meanwhile, fig. 20(b) shows that when there are two transmission antennas in the transmitter, one of the two transmission antennas is selected using the first 1 bit of the 3-bit stream, and the other 2 bits are transmitted by QPSK modulation.

The 2 bits of fig. 20(a) and the 1 bit of fig. 20(b) used for antenna selection are not actually transmitted from the transmitter to the receiver. However, if the receiver detects the antenna through which the received signal or symbol is transmitted, the receiver can identify the corresponding bit.

That is, referring to fig. 20, if there are four transmit antennas, 2-bit information may indicate each antenna, and if there are two transmit antennas, 1-bit information may indicate each antenna. Accordingly, the receiver can detect specific information of 2 bits or 1 bit by identifying an antenna through which a signal is transmitted.

Therefore, if the number of transmission antennas increases, the number of bits required to select antennas in the transmitter increases, so that the amount of data or control information matching the corresponding bits increases. In this regard, the SM scheme is suitable for antenna transmission techniques such as massive MIMO.

The receiver may detect an antenna or an antenna group for a data signal transmitted using the SM scheme and then decode the received data by performing demodulation. At this time, the receiver can detect an antenna or an antenna group having transmitted a data signal using the decision metric represented in equation 4.

[ equation 4]

Y1＝r1·h^*＝|h|²d+h^*·n,r1＝h·d1+n

Y2＝r2·g^*＝g^*·n,r2＝g·d2+n

In equation 4, Y1 indicates a decision metric for an antenna (port) that has transmitted a data signal, and Y2 indicates a decision metric for an antenna (port) that has not transmitted a data signal. At this time, r1 and r2 denote received symbols, h and g denote radio channels through which the respective received symbols pass, d1 and d2 denote noise of data signals actually transmitted, and n denotes noise of the respective radio signals.

The receiver may recognize whether the data signal of the kth antenna or antenna group has been transmitted through z (k) -max (Y1, Y2). Therefore, if

k 1., M (M: # of transmit antenna), the receiver may decide the transmit antenna through which to send the data signal. After detecting the antenna or the antenna group, the receiver may demodulate the received data through a demodulation program.

When the transmitter transmits data/control signals by using the SM scheme, the transmission antenna may be an individual antenna or an antenna group, or may be an individual antenna port or an antenna port group. In the embodiment of the present invention, it is assumed that the transmitting antenna is a separate antenna for convenience of explanation. However, the embodiments of the present invention can be equally applied even to a case in which the transmission antennas configure the antenna group.

3.1 method for Link Adaptation for SM schemes

If the SM scheme is used, some bit streams transmitted from the transmitter are used for antenna selection and other bit streams are used for data transmission. At this time, the plurality of transmission antennas may have their respective channel characteristics different from each other. In this case, the link adaptation method may be considered as follows.

(1) The method comprises the following steps: a method for applying the same Modulation and Coding Scheme (MCS) to data transmitted from all antennas or all antenna groups.

(2) The method 2 comprises the following steps: a method for applying MCS, which are respectively different from each other, to data transmitted to each antenna or antenna group.

In case of method 1, there is an advantage in that CSI feedback can be reduced, however, MCS level is determined according to the worst channel, and thus overall data throughput may be reduced. In case of the method 2, there is an advantage in that an MCS level optimized for a state of each channel can be set, however, overhead for performing CSI feedback of each channel may increase.

Therefore, the method 1 can be used for the case in which the channel status is good, and the method 2 can be used for the case in which the channel status is not good. Likewise, method 1 and method 2 may be used for semi-static changes.

3.2 spatial modulation scheme based on spatial multiplexing

A method for extending the SM scheme to the spatial multiplexing scheme will be suggested below. However, for convenience of explanation, it is assumed that the number of transmission antennas of the transmitter is 4. The method to be described below can be applied even equally to the case where the number of transmission antennas is 2, 3, or 5 or more.

For example, in case of rank 1 transmission, since the transmitter selects and transmits one of four transmission antennas, the number of bits of additional transmission used when the SM scheme is used may be set to be one bit

That is, the transmitter may use 2-bit selectionAntennas are selected and other bits may be transmitted by mapping them to constellation points.

In this way, in case of rank 2, since the transmitter selects two transmission antennas and transmits a data signal, the usage corresponds to

To select the transmit antenna and transmit other bit streams by modulation.

Likewise, in case of rank 3, the transmitter may use

Three transmit antennas are selected and other bit streams are transmitted by modulation. However, in case of rank 4, since the transmitter transmits a data signal by using all antennas, a data bit stream can be transmitted without selecting antennas through modulation.

Fig. 21 is a diagram illustrating one of methods of transmitting and receiving data/control signals by using a Spatial Modulation (SM) scheme to which spatial multiplexing is applied.

The above equation 4 relates to a method of detecting an antenna having transmitted data in a receiver if spatial multiplexing is not used. Hereinafter, a method of transmitting and receiving data/control signals if spatial multiplexing is used will be described.

Referring to fig. 21, a transmitter configures a data signal or a control signal by applying an SM scheme. That is, the transmitter may configure the data signal by using the data bits to be transmitted and the information bits added by the antenna selection (S2110).

At this time, since the transmitter uses a spatial multiplexing scheme, data streams corresponding to one or more ranks can be transmitted. However, in this case, the receiver should know information about the rank of the data stream transmitted from the transmitter in order to identify the number of antenna ports of the transmitter. Accordingly, the transmitter transmits rank information to the receiver, and at this time, the rank information may be transmitted through a downlink control signal (e.g., a PDCCH signal) (S2120).

The transmitter may transmit the data and control signals configured in step S2110 and a reference signal for a specific UE, e.g., a DM-RS (demodulation reference signal), to the receiver (S2130).

DM-RS, which is a UE-specific signal, is used for PDSCH signal transmission, and a different DM-RS is used for each antenna port. Accordingly, the receiver can identify an antenna port through which a data signal is transmitted during DM-RS reception. The receiver may exactly detect the transmission antenna port based on the rank information and DMRS received in steps S2120 and S2130, identifying the number of antenna ports that have been used for SM data transmission (S2140).

The receiver may derive a bit stream for antenna selection based on the rank information and the antenna ports received and detected in step S2130. Accordingly, the receiver may demodulate a data signal and a control signal transmitted from the base station based on the decoded signal and the derived bit stream (S2150).

If the UE-specific reference signal is used in step S2130 of fig. 21, it is preferable that the transmitted control signal be an E-PDCCH (enhanced PDCCH) transmitted from the PDSCH region.

In case of the LTE/LTE-a system, a bit stream configures OFDM symbols, a plurality of OFDM symbols (e.g., 6 or 7 symbols) configure one slot, and one subframe is configured by two slots. Accordingly, if the SM scheme is applied to the LTE/LTE-a system, the SM scheme may be applied through one unit of a bit stream, an OFDM symbol, a slot, or a subframe.

For example, if the SM scheme is applied to the LTE/LTE-a system in one unit of a bit stream, it is advantageous in that bits for selecting a transmission antenna are additionally transmitted in addition to modulation symbols. Also, if the SM scheme is applied to the LTE/LTE-a system in one unit of an OFDM symbol, bits for selecting a transmission antenna may be additionally transmitted in addition to bits corresponding to the OFDM symbol. If the SM scheme is applied to the LTE/LTE-a system in one unit of time slot or subframe, a data signal equivalent to the number of bits required to select a transmission antenna or antenna port may be additionally transmitted every time slot or every subframe. For example, if the SM scheme is applied to the LTE/LTE-a system in one unit of a subframe and the transmitter uses two transmit antennas, it is advantageous in that the transmitter additionally transmits 1 bit. At this time, the added 1 bit may be used to transmit data or control information.

3.3 method for transmitting control information

The case in which the control signal is transmitted together with the DM-RS has been described with reference to fig. 21. In this case, preferably, the control signal is an E-PDCCH signal. The E-PDCCH signal can be transmitted even in the case of the SM scheme described in section 3.1, and the SM scheme can be applied to transmission of a PDCCH signal even as a normal control signal.

A method for transmitting a control signal by using the SM scheme will be described below.

3.3.1 PHICH Transmission based on SM scheme

An E-PDCCH signal is transmitted through a PDSCH region. The transmitter may select one of the multiple antennas to transmit the E-PDCCH. At this time, the transmitter may transmit the PHICH signal by using bits required to select one of the multiple antennas.

For example, if the transmitter includes two transmit antennas, the transmitter may use 1 bit required for selecting the transmit antennas to transmit the PHICH as an ACK/NACK response to the PUSCH. That is, a set of EPDCCH candidates is configured to include a first antenna port and a second antenna port of the plurality of ports. In this case, if the E-PDCCH signal is transmitted through a first antenna port of the two antenna ports, ACK for the PUSCH may be set, and if the E-PDCCH signal is transmitted through a second antenna port of the two antenna ports, NACK for the PUSCH may be set. At this time, it may be assumed that the E-PDCCH signal is control information having PDSCH scheduling information for UEs scheduled by a PUSCH.

In more detail, a transmitter, which has received a PDSCH signal from a receiver, detects ACK/NACK for the corresponding PDSCH signal. Thereafter, the transmitter may transmit the E-PDCCH signal together with PHICH information by using the SM scheme when transmitting the E-PDCCH signal instead of transmitting a separate PHICH signal. That is, the transmitter may select one of a plurality of antennas by using one or more bits required to select the corresponding antenna to transmit an E-PDCCH signal to the receiver, and transmit PHICH information. Accordingly, the receiver can know PHICH information by detecting an antenna port to which an E-PDCCH signal is transmitted.

3.3.2 method for sending NDI information

The transmitter may transmit a New Data Indication (NDI) bit of a bit for configuring a DCI format of the E-PDCCH signal by using the SM scheme. For example, the transmitter may transmit the NDI information by carrying the NDI information in bits used to select transmit antennas. If an E-PDCCH signal is transmitted through a first antenna port of two antenna ports of a transmitter, it may mean 'NDI ═ not signaled (i.e., retransmission)'. If an E-PDCCH signal is transmitted through a second antenna port of two antenna ports of a transmitter, it may mean 'NDI ═ signaled (i.e., new transmission)'. Accordingly, the receiver may acquire NDI information by detecting an antenna through which the received E-PDCCH signal is transmitted. In this way, the transmitter may reduce the size of the DCI format configuring the E-PDCCH signal.

3.3.3 method for transmitting TPC information

Transmit Power Control (TPC) bits configuring information bits of a DCI format of an E-PDCCH signal may be transmitted using spatial modulation. For example, the transmitter may transmit the TPC information by using a bit for selecting a transmit antenna for transmitting the E-PDCCH signal. If an E-PDCCH signal is transmitted through a first antenna port of the two antenna ports, it corresponds to a 'TPC ═ UP (power UP)' command. Likewise, if an E-PDCCH signal is transmitted through the second of the two antenna ports, it corresponds to a 'TPC ═ DOWN (power DOWN)' command.

Accordingly, the receiver can acquire TPC information by detecting an antenna through which the E-PDCCH signal is transmitted. In this way, the transmitter may reduce the size of the DCI format configuring the E-PDCCH signal.

3.4 method for transmitting data signals

During data transmission, channel coding is applied to a general communication system. Likewise, LTE/LTE-a systems employ Turbo coding during channel coding. The coded bits encoded using the turbo encoder are classified into systematic bits (S) and parity bits (P).

A case in which the SM scheme is applied to systematic bits and parity bits of the configuration data signal will be described below. In general, coding performance is more affected by systematic bits than by parity bits. Therefore, if systematic bits are transmitted more reliably than parity bits, it helps to improve the decoding performance of the data signal. In this regard, if the SM scheme is applied, the transmitter may additionally transmit a bit stream for selecting a transmission antenna to the bit stream mapped into the modulation symbol.

A demodulation procedure for a receiver of the modulation symbols is performed after detecting the transmit antenna that has transmitted the modulation symbols. Accordingly, systematic bits can be arranged among bits for selecting transmission antennas, thereby improving data transmission performance. The transmitter may match the parity bits and the modulation symbols after the bits used to select the transmit antennas are all used for the systematic bits.

Fig. 22 is a diagram illustrating a method of applying a Spatial Modulation (SM) scheme to systematic bits and parity bits of a configuration data signal. In particular, fig. 22(a) relates to a method of transmitting systematic bits by using bits for antenna selection and transmitting parity bits by the above modulation. Unlike fig. 22(a), fig. 22(b) shows a method for transmitting parity bits by matching the parity bits and bits for antenna selection, and transmitting systematic bits by modulation.

In the case of fig. 22(b), the receiver detects the transmitting antenna through which the data signal is transmitted when detecting the received data signal. A method for detecting a transmit antenna may be performed using equation 4 above or the method described with reference to fig. 21. A receiver having detected the transmit antennas may detect bits for selecting the corresponding transmit antennas, and may detect parity bits through the detected bits. The receiver may then demodulate the systematic bits by demodulating the received data signal.

Fig. 23 is a diagram illustrating a method of configuring a data signal in a transmitter by applying a Spatial Modulation (SM) scheme.

It is assumed that the transmitter includes two transmit antennas or two transmit antenna groups. If the transmission antennas are configured by two groups, the numbers of antennas belonging to each group may be the same as each other or different from each other.

Referring to fig. 23, the SM scheme is applied to an 1/3 turbo-coded bit stream consisting of 16-bit systematic bits and 32-bit parity bits. The bit stream shown in fig. 23 may be transmitted using the method described in fig. 22. If systematic bits or parity bits are transmitted using the antenna selection scheme, '0' denotes data bits mapped into antenna port 'x', and '1' denotes data bits mapped into antenna port 'y'. Data bits not using the antenna selection scheme are transmitted by being modulated by a modulation scheme provided via a modulator.

Fig. 24 is a diagram illustrating an example of a method for transmitting turbo-coded bits by applying a Spatial Modulation (SM) scheme to the turbo-coded bits.

Fig. 24(a) shows a method of modulating parity bits P1 and P2 by connecting them in series, and fig. 24(b) shows a method of modulating parity bits P1 and P2 by connecting them in parallel. For convenience of explanation, the method of fig. 24 is illustrated using parity bits illustrated in fig. 23. Also, the method of fig. 24 may be applied when systematic bits are transmitted to a receiver as additional bits according to an antenna selection scheme in accordance with the SM scheme described in fig. 22(a), and parity bits are modulated.

If the bits in the method of fig. 24 are transmitted according to the SM scheme described in fig. 22(b) and only one of P1 and P2 is transmitted according to the antenna selection scheme, P1 or P2 and systematic bits can be modulated through connection in the manner described in fig. 24.

The above embodiments of the present invention have been described based on the transmitter being an eNB and the receiver being a UE. However, the above embodiments may be equally or similarly applied even to the case where the transmitter is a UE and the receiver is an eNB. For example, in case of transmitting a PUSCH signal for transmitting ACK/NACK for a PDSCH signal, the ACK/NACK signal may be transmitted according to the SM scheme. In addition, the uplink control information may be transmitted through the SM scheme.

In the case of the method of transmitting a control signal or control information by using the SM scheme described in section 3.3, the number of bits of control information to be transmitted is not large. Therefore, the corresponding SM scheme can be applied even in a case where the number of transmission antennas is small. In this regard, the methods described in section 3.3 may be applied to legacy LTE/LTE-a systems. However, in the method for transmitting a data signal described in section 3.4, it is general that the number of data bits to be transmitted is large. Therefore, the method of section 3.4 can be used in a large-scale MIMO environment or a small cell environment.

4. Device for measuring the position of a moving object

The apparatus illustrated in fig. 25 means an apparatus capable of implementing the method described before with reference to fig. 1 to 24.

The UE may serve as a transmitting end on the UL and as a receiving end on the DL. The eNB may serve as a receiving end on UL and a transmitting end on DL.

That is, each of the UE and the eNB may include a transmitter (Tx)2540 or 2550 and a receiver (Rx)2560 or 2570 for control transmission and reception of information, data, and/or messages; and an antenna 2500 or 2510 for transmitting and receiving information, data, and/or messages.

Each of the UE and the BS may further include a processor 2520 or 2530 for implementing the aforementioned embodiments of the present disclosure and a memory 2580 or 2590 for temporarily or permanently storing the operation of the processor 2520 or 2530.

Embodiments of the present invention can be performed using the aforementioned elements and functions of the UE and the aforementioned eNB. For example, the processors of the UE and the eNB may transmit data bits or control information by applying the SM scheme by means of a combination of the methods described in the foregoing sections 1 to 3. The details thereof will be understood with reference to section 3.

Tx and Rx of the UE and eNB may perform packet modulation/demodulation functions for data transmission, high speed packet channel coding functions, OFDMA packet scheduling, TDD packet scheduling, and/or channelization. Each of the UE and the eNB of fig. 25 may further include a low power Radio Frequency (RF)/Intermediate Frequency (IF) module.

Meanwhile, the UE may be any one of a Personal Digital Assistant (PDA), a cellular phone, a Personal Communication Service (PCS) phone, a Global System for Mobile (GSM) phone, a Wideband Code Division Multiple Access (WCDMA) phone, a Mobile Broadband System (MBS) phone, a handheld PC, a laptop PC, a smart phone, a multi-mode multi-band (MM-MB) terminal, and the like.

A smart phone is a terminal that takes advantage of the advantages of both mobile phones and PDAs. Which incorporates the PDA's functions, i.e., scheduling and data communications such as facsimile transmission and reception and internet connection, into a mobile phone. The MB-MM terminal refers to a terminal having a multi-mode chip built therein and operating in any one of a mobile internet system and other mobile communication systems (e.g., CDMA2000, WCDMA, etc.).

Embodiments of the present disclosure may be implemented by various means, for example, hardware, firmware, software, or a combination thereof.

In a hardware configuration, the method according to an embodiment of the present disclosure may be implemented by one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), digital signal processing devices (DSDPs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or the like.

In a firmware or software configuration, the method according to the embodiment of the present disclosure may be implemented in the form of a module, a procedure, a function, etc. performing the above-described functions or operations. The software codes may be stored in memory 2580 or 2590 and executed by processor 2520 or 2530. The memory is located inside or outside the processor, and may transmit and receive data to and from the processor via various known means.

It will be apparent to those skilled in the art that the present disclosure may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the present disclosure. The above embodiments are therefore to be construed in all aspects as illustrative and not restrictive. The scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the description above, and all changes that come within the meaning and range of equivalency of the appended claims are intended to be embraced therein. It is obvious to those skilled in the art that claims that are not explicitly cited in each other in the appended claims may be presented in combination in accordance with the embodiments of the present disclosure or included as a new claim by subsequent amendment after the application is filed.

Industrial applicability

The present disclosure is applicable to various wireless access systems including a 3GPP system, a 3GPP2 system, and/or an IEEE802. xx system. In addition to these wireless access systems, embodiments of the present disclosure may be applicable to all technical fields in which wireless access systems discover their applications.

Claims (3)

1. A method for receiving acknowledgement/negative acknowledgement, ACK/NACK, information by a receiver based on a spatial modulation, SM, scheme in a wireless access system, the method comprising:

sending data;

one of the first and second demodulation reference signals DM-RS is received through one of two antenna ports used for reception of an enhanced physical downlink control channel E-PDCCH,

wherein the first DM-RS is received through a first of the two antenna ports and the second DM-RS is received through a second of the two antenna ports;

information on one of the two antenna ports is obtained based on the received DM-RS,

receiving an E-PDCCH through one of two antenna ports;

obtaining physical hybrid ARQ indicator PHICH information for the data,

wherein whether ACK or NACK is configured as the PHICH information is based on which of two antenna ports is used for reception of the E-PDCCH,

wherein ACK is configured as the PHICH information when the first antenna port is used, and

wherein NACK is configured as the PHICH information when the second antenna port is used,

wherein whether the transmission power is increased or decreased is based on which antenna port is used for reception of the E-PDCCH in both antenna ports, an

Wherein the E-PDCCH includes information that transmission power is to be increased when a first antenna port is used, and the E-PDCCH includes information that transmission power is to be decreased when a second antenna port is used.

2. The method of claim 1, wherein the E-PDCCH includes scheduling information for Physical Downlink Shared Channel (PDSCH) signals.

3. The method of claim 1, wherein the E-PDCCH is received from a data region.

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